Method and a device for sequencing the ZC sequences of the random access channel

ABSTRACT

The present invention discloses a method and a device for sequencing the ZC sequences of the random access channel. The method for sequencing the ZC sequences includes the following steps: Step  202 , ZC sequences are divided into a plurality of groups according to the cubic metrics of the ZC sequences; Step  204 , the ZC sequences are sequenced, according to the maximum cyclic shift supported by the ZC sequences under a high speed circumstance, within each group to form a plurality of sub-groups; and Step  206 , the ZC sequences within each of the plurality of sub-groups are sequenced according to the cubic metrics of the ZC sequences, wherein, the adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of the two adjacent groups are sequenced in the same order. Thereby, the sequences could be assigned according to the CMs, and the sequence fragments could be collected for use.

FIELD OF THE INVENTION

The present invention relates to communication field, in particular to a method and a device for sequencing the ZC sequences of the random access channel.

BACKGROUND OF THE INVENTION

In Long Term Evolution (LTE for short) system, cyclic shift sequences of Zadoff-Chu (ZC for short) sequences are used as preambles by the Random Access Channel (RACH for short). These cyclic shift sequences are also referred to as Zero Correlation Zone (ZCZ for short) sequences.

In practical systems, after a mobile phone is powered on, firstly, downlink synchronization is first performed, and then the detection of the Broadcast Channel (BCH for short) is initiated. A base station informs, via the BCH channel, the mobile phone the index and the step length of the cyclic shift of the first ZC sequence available for the RACH of the current cell. According to the index, the mobile phone makes use of certain mapping rule to calculate the serial number of the corresponding ZC sequence, and then, generates usable ZCZ sequences according to the step length of the cyclic shift and a certain “cyclic shift limitation rule”. If the number of the ZCZ sequences is smaller than a certain threshold P, the mobile phone automatically increments the sequence index, and continuously generates the ZCZ sequences using the next ZC sequence, until the total number of the ZCZ sequences is larger than or equal to P. Finally, the mobile phone randomly selects one sequence from all the generated usable ZCZ sequences as a preamble to be sent.

In a high speed circumstance, the frequency offset caused by Doppler Effect will generate, during the process of the preamble detection, a correlation peak alias, which will lead to a timing offset and a false detection. This problem is settled in LTE system through limiting the use of some cyclic shifts according to a certain rule, which is the mentioned “cyclic shift limitation rule”. Meanwhile, the cyclic shift limitation rule also limits the maximum cyclic shift N_(CS) corresponding to each ZC sequence, and this maximum cyclic shift directly determines the maximum cell radius supported by each ZC sequence. Supposing that the distance between the correlation peak and the correlation peak alias thereof is du, the relation between the maximum cyclic shift N_(CS) and du is: N _(CS)=min(du, N _(ZC)−2·du)  (1)

wherein, N_(ZC) is the length of a ZC sequence, du can be calculated by the following formula:

$\begin{matrix} {{du} = \left\{ \begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix} \right.} & (2) \end{matrix}$

wherein, u is the serial number of the ZC sequence, and m is the minimum positive integer which makes

$\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.

The mapping process between the indices and the serial numbers of the ZC sequences is actually the process of re-sequencing the ZC sequences. At present, there are mainly two sequencing methods: one is to sequence according to the cubic metric (CM for short, it is a standard for measuring the Peak-to-Average Power Ratio of the emitted data, the larger the CM is, the higher the Peak-to-Average Power Ratio is) of the ZC sequences, and the other is to sequence according to the maximum cell radius supported by each ZC sequence. The first method is advantageous in that network planning can be conveniently performed according to the CM of a root sequence so as to assign the sequences with smaller CMs to the cells with larger radius, and the sequences with close CMs to the same cell. Its shortcoming lies in that sequence fragments will be generated, which will cause the waste of the sequences. In other words, during the process of generating the ZCZ sequences with the continuous incrementation of the sequence index, if the maximum cell radius supported by a ZC sequence is smaller than the radius of the current cell, this sequence neither could be used by the current cell, nor it could be used by other cells having radiuses smaller than the maximum cell radius supported by this ZC sequence (this is because that the index is continuously incremental, as shown in FIG. 1). The second method is advantageous in avoiding the generation of the sequence fragments, that is disadvantageous in that the CMs of the ZC sequences assigned to a cell differs greatly from each other so that sequence planning can not be performed according to the CM.

SUMMARY OF THE INVENTION

In view of the above mentioned one or more problem, the present invention provides a method and a device for sequencing the ZC sequences of the random access channel.

The method for sequencing the ZC sequences of the random access channel according to the embodiments of the present invention comprises the following steps: Step 202, Nq ZC sequences are divided into a plurality of groups according to the cubic metrics of the ZC sequences; Step 204, the ZC sequences are sequenced, according to the maximum cyclic shift supported by the ZC sequences under a high speed circumstance, within each group to form a plurality of sub-groups; and Step 206, the ZC sequences are sequenced within each of the plurality of sub-groups according to the cubic metrics of the ZC sequences, wherein, the adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of the two adjacent groups are sequenced in the same order.

Wherein, in Step 202, Nq ZC sequences are divided into G groups, wherein, 1≦G≦Nq, the relation between the serial number of each of the plurality of groups and the cubic metrics of the ZC sequences in each of the plurality of groups is: the cubic metrics of the ZC sequences in Group i are smaller than the cubic metrics of the ZC sequences in Group i+1, or the cubic metrics of the ZC sequences in Group i are larger than the cubic metrics of the ZC sequences in Group i+1. Specifically, Nq ZC sequences may be divided into two groups according to the cubic metrics of Quadrature Phase Shift Keying.

Wherein, in Step 202, firstly, Nq ZC sequences are sequenced, in the decreasing order or in the increasing order, according to the cubic metrics of the ZC sequences, and then, the sequencing result is divided into a plurality of groups according to one or more cyclic shift thresholds.

Wherein, the sequencing process in Step 204 may be performed in the increasing order or in the decreasing order, and the adjacent groups are sequenced in different orders.

Wherein, the sequencing process in Step 204 needs to be performed according to a certain granularity. The granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)}, and P_(i) ^(g)<P_(i+1) ^(g), thus, (1) the sequencing performed in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g); (2) the sequencing performed in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(s−i+2) ^(g) and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i) ^(g).

Wherein, the maximum cyclic shift N_(CS)=min(du, N_(ZC)−2·du), wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of the ZC sequence. The distance between the correlation peak and the correlation peak alias thereof is

${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of the ZC sequence, and m is the minimum positive integer which makes

$\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.

The device for sequencing the ZC sequences of the random access channel according to the embodiments of the present invention comprises: a first group dividing unit, configured to divide Nq ZC sequences into a plurality of groups according to the cubic metrics of the ZC sequences of the random access channel; a to second group dividing unit, configured to sequence the ZC sequences within each group to form a plurality of sub-groups, according to the maximum cyclic shift supported by the ZC sequences under a high speed circumstance; and a sequencing unit, configured to sequence the ZC sequences in each of the plurality of sub-groups according to the cubic metrics of the ZC sequences, wherein, the adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of the two adjacent groups are sequenced in the same order.

Wherein, the first group dividing unit divides Nq ZC sequences into G groups, wherein, 1≦G≦Nq, the relation between the serial number of each of the plurality of groups and the cubic metrics of the ZC sequences in each of the plurality of group is: the cubic metrics of the ZC sequences in Group i are smaller than the cubic metrics of the ZC sequences in Group i+1, or the cubic metrics of the ZC sequences in Group i are larger than the cubic metrics of the ZC sequences in Group i+1. Specifically, the first group dividing unit divides the Nq ZC sequences into two groups using the cubic metrics of Quadrature Phase Shift Keying as a threshold.

Wherein, the second group dividing unit divides the ZC sequences in each sub-group into a plurality of sub-groups according to one of the following principles: the maximum cyclic shift supported by the ZC sequences in Sub-group i under the high speed circumstance is smaller than the maximum cyclic shift supported by the ZC sequences in Sub-group i+1 under the high speed circumstance, the maximum cyclic shift supported by the ZC sequences in Sub-group i under the high speed circumstance is larger than the maximum cyclic shift supported by the ZC sequences in Sub-group i+1 under the high speed circumstance, wherein, the second group dividing unit applies different principles to the sub-groups in adjacent groups.

Wherein, the sequencing process of the second group dividing unit may be performed in the increasing order or in the decreasing order, and the adjacent groups should be sequenced in different orders.

Wherein, the sequencing process of the second group dividing unit needs to be performed according to a certain granularity. The granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)}, and P_(i) ^(g)<P_(i+1) ^(g), thus, (1) performing the sequencing in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g); (2) performing the sequencing in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P^(s−i+2) ^(g), and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g).

Wherein, the maximum cyclic shift N_(CS)=min(du, N_(ZC)−2·du), wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of the ZC sequence. The distance between the correlation peak and the correlation peak alias thereof is

${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of the ZC sequence, and m is the minimum positive integer which makes

$\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.

The present invention not only enables the assignment of the sequences according to the CMs, but also enables the collection of the sequence fragments for use, so that the generation of sequence fragments can be avoided. Meanwhile, the present invention is fully compatible to the first and the second re-sequencing methods described in the Background of the Invention, without introducing any extra signaling cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrated here provide a further understanding of the present invention and form a part of the present application. The exemplary embodiments and the description thereof are used to explain the present invention without unduly limiting the scope of the present invention, wherein:

FIG. 1 is a schematic diagram of the generation of the sequence fragments in relevant techniques;

FIG. 2 is a flowchart of the method for sequencing the ZC sequences of the random access channel according to the embodiments of the present invention;

FIG. 3 is a schematic diagram of Step 202 in the method illustrated in FIG. 2;

FIG. 4 is a schematic diagram of Step 204 in the method illustrated in FIG. 2;

FIG. 5 is a schematic diagram of Step 206 in the method illustrated in FIG. 2 (in view of the cubic metric);

FIG. 6 is a schematic diagram of Step 206 in the method illustrated in FIG. 2 (in view of the maximum cyclic shift supported by the ZC sequences); and

FIG. 7 is a block diagram of the device for sequencing the ZC sequences of the random access channel according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The embodiments of the present invention will be described hereinafter in detail in conjunction with the drawings thereof.

The method for sequencing the ZC sequences of the random access channel according to an embodiment of the present invention is described with reference to FIG. 2. As shown in FIG. 2, the method for sequencing the ZC sequences comprises the following steps:

Step 202, the ZC sequences are divided into a plurality of groups according to the cubic metrics of the ZC sequences. Specifically, there are various principles for the group division. For example, the CM of data modulated using Quadrature Phase Shift Keying (QPSK for short) is 1.2 dB, and this value can be used as a threshold to divide the ZC sequences into two groups: the CMs of the ZC sequences in the first group is smaller than or equal to 1.2 dB; and the CMs of the ZC sequences in the second group is larger than 1.2 dB. Wherein, the following method can be used to carry out this step: sequencing the cubic metrics of the ZC sequences in the increasing order; and dividing the sequencing result into two groups using the cubic metric (1.2 dB) of QPSK as a threshold.

Step 204, the ZC sequences are sequenced, according to the maximum cyclic shift supported by the ZC sequences under a high speed circumstance, within each group to form a plurality of sub-groups. The sequencing process may be performed in the increasing order or in the decreasing order, and the adjacent groups (the groups obtained through Step 202) shall be sequenced in different orders. Moreover, the sequencing process needs to be performed according to a certain granularity. The granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)}, and P_(i) ^(g)<P_(i+1) ^(g), thus, (1) the sequencing performed in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g); (2) the sequencing performed in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(s−i+2) ^(g) and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g).

Step 206, in each sub-group, the sequencing is performed according to the CM values of the ZC sequences, and the adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of the two adjacent groups are sequenced in the same order.

Wherein, since performing the sequencing according to the maximum cell radius supported by the ZC sequences only needs to know the relative relation between the maximum cell radiuses supported by respective ZC sequences, and since the maximum cell radius supported by each ZC sequence is directly determined by the maximum cyclic shift N_(CS) of each ZC sequence, the sequencing process is equivalent to performing a sequencing according to N_(CS). Wherein, N_(CS)=min(du, N_(ZC)−2·du), du is the distance between the correlation peak and the correlation peak alias thereof, and N_(ZC) is the length of a ZC sequence. The distance between the correlation peak and the correlation peak ali as thereof is

${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of the ZC sequence, and m is the minimum positive integer which makes

$\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.

For example, the length N_(ZC) of the ZC sequence is 839, and each cell needs to generate 64 usable ZCZ sequences. Firstly, the ZC sequences are divided into two groups according to the CM value (1.2 dB) of the QPSK, wherein, the CM value of the first group is smaller than 1.2 dB, and the CM value of the second group is larger than 1.2 dB (as shown in FIG. 3); secondly, the sequencing is performed according to the granularity {15, 18, 22, 26, 32, 38, 46, 55, 68, 82, 100, 128, 158, 202, 237}, and according to the maximum cyclic shift supported by the ZC sequences under the high speed circumstance, and the sequencing is performed in the increasing order in the low CM group, while in the decreasing order in the high CM group, and the ZC sequences are divided into 16 sub-groups in each group (as shown in FIG. 4); finally, the sequencing is performed in each sub-group according to the CMs of the sequences, and the adjacent sub-groups are sequenced in different orders (as shown in FIGS. 5 and 6). The sequencing result is shown in table 1

TABLE 1 SG1 SG2 SG3 SG4 SG5 SG6 SG7 SG8 SG9 SG10 SG11 SG12 SG13 SG14 SG15 SG16 low cubic metric group 129 56 80 35 808 24 86 744 217 12 228 832 687 5 225 3 710 783 759 804 31 815 753 95 622 827 611 7 152 834 614 836 140 112 42 766 811 791 761 202 128 816 227 831 144 806 615 820 699 727 797 73 28 48 78 637 711 23 612 8 695 33 224 19 719 148 40 693 30 771 796 649 697 34 132 823 134 788 618 817 120 691 799 146 809 68 43 190 142 805 707 16 705 51 221 22 629 812 74 39 658 122 37 706 792 138 764 220 798 210 27 765 800 181 717 802 133 47 701 75 619 41 168 29 661 819 702 203 793 143 64 640 740 127 38 671 810 178 20 137 636 46 696 775 199 99 712 801 84 703 818 125 721 207 704 57 162 743 147 44 755 136 21 714 118 632 135 782 677 96 692 795 105 151 729 660 161 735 176 97 124 52 734 688 110 179 678 104 663 742 715 787 746 89 694 201 101 119 166 193 45 93 750 145 638 738 720 673 646 794 70 736 709 666 108 681 172 205 63 769 103 130 173 731 158 667 634 776 779 61 223 733 631 164 664 633 772 60 778 616 106 208 675 175 206 67 2 784 756 655 665 652 723 72 837 55 83 184 174 187 116 767 1 824 748 197 668 676 679 76 838 15 91 642 171 163 160 763 825 66 648 170 185 186 745 14 773 191 669 654 653 94 53 718 87 639 167 737 786 121 752 200 672 102 10 141 670 114 760 90 829 698 169 725 79 749 9 149 751 189 754 109 830 690 88 650 85 730 623 107 724 77 165 216 732 115 762 674 218 758 194 92 728 621 81 645 747 111 82 195 781 209 757 644 58 630 100 647 62 204 739 192 111 635 98 182 69 117 741 657 770 722 768 682 54 651 71 157 785 188 59 156 803 680 780 683 36 159 65 211 807 198 774 628 32 641 789 154 25 113 50 685 814 726 49 716 821 656 790 123 18 183 813 700 828 659 26 139 11 180 822 212 835 177 17 627 4 662 826 686 643 13 153 196 6 213 155 833 626 684 215 625 624 214 689 126 150 713 708 131 219 620 617 222 613 226 high cubic metric group 609 323 237 509 257 346 608 546 242 317 603 484 604 530 367 503 230 516 602 330 582 493 231 293 597 522 236 355 235 309 472 336 232 320 600 338 566 500 260 288 274 307 303 434 572 265 296 534 607 519 239 501 273 339 579 551 565 532 536 405 267 574 543 305 577 334 244 498 584 351 268 284 402 553 356 435 302 233 466 262 505 595 341 255 488 571 555 437 286 483 404 537 606 373 587 359 243 499 254 306 563 471 383 552 433 280 252 480 596 340 585 533 276 368 456 287 406 559 418 544 275 497 245 550 430 253 482 573 560 421 295 564 342 594 289 409 586 357 266 279 416 454 561 301 588 439 398 583 510 578 419 423 385 278 538 251 400 441 256 329 261 420 426 292 589 366 412 461 549 263 240 413 547 250 473 427 378 290 576 599 428 291 246 401 467 465 535 258 411 548 593 438 372 374 304 581 463 381 417 468 557 415 308 610 376 458 422 371 282 424 531 229 444 399 248 408 436 569 358 395 440 591 431 403 270 481 283 380 445 464 396 598 316 556 459 394 375 443 241 523 285 442 393 249 447 554 397 446 590 392 379 470 370 269 448 460 369 469 570 391 449 462 365 238 457 390 377 474 601 382 363 429 300 605 389 476 410 539 234 450 455 407 299 294 384 432 540 545 451 281 475 542 388 558 364 297 386 425 362 528 453 414 477 311 478 592 541 344 361 247 298 495 452 562 527 345 387 277 312 494 360 568 313 318 479 271 526 521 529 272 525 331 310 567 314 508 485 264 353 514 354 575 486 325 511 580 487 321 328 259 352 518 524 343 315 496 337 512 502 327 349 350 490 489 504 326 335 513 515 319 324 520 332 507 506 333 491 348 492 347 517 322

After the above sequencing process is completed, the mapping relation between the sequence indices and the serial numbers of the ZC sequences can be obtained. As to a practical system, the mapping relation can be stored in the memories of a mobile phone and a base station. After the base station informs, via the BCH channel, the mobile phone the sequence index, the mobile phone can find the serial number of the ZC sequence corresponding to the index according to the mapping relation, and then generate usable ZCZ sequences according to the step length of cyclic shift and the cyclic shift limitation rule. If the number of the ZCZ sequences is smaller than 64, the mobile phone increments the index, and continuously generates ZCZ sequences using the next ZC sequence until the total number of the ZCZ sequences reaches 64. Finally, the mobile phone randomly selects one sequence from all the generated ZCZ sequences as a preamble to be sent.

The device for sequencing the ZC sequences of the random access channel according to an embodiment of the present invention is described with reference to FIG. 7. As shown in FIG. 7, the device for sequencing the ZC sequences of the to random access channel comprises: a first group dividing unit 702, configured to divide Nq ZC sequences into a plurality of groups according to the cubic metrics of the ZC sequences of the random access channel; a second group dividing unit 704, configured to sequence the ZC sequences within each group to form some sub-groups according to the maximum cyclic shift supported by the ZC sequences under high speed circumstance; and a sequencing unit 706, configured to sequence the ZC sequences in each of the plurality of sub-groups according to the cubic metrics of the ZC sequences, wherein, the adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of the two adjacent groups are sequenced in the same order.

Wherein, the first group dividing unit divides the Nq ZC sequences into G groups, wherein, 1≦G≦Nq, the relation between the serial number of each group and the cubic metrics of the ZC sequences in each group is: the cubic metrics of the ZC sequences in Group i is smaller than the cubic metrics of the ZC sequences in Group i+1, or the cubic metrics of the ZC sequences in Group i is larger than the cubic metrics of the ZC sequences in Group i+1. Specifically, the first group dividing unit divides the Nq ZC sequences into two groups using the cubic metrics of Quadrature Phase Shift Keying as a threshold.

Wherein, the second group dividing unit divides the ZC sequences in each sub-group into a plurality of sub-groups according to one of the following principles: the maximum cyclic shift supported by the ZC sequences in Sub-group i under the high speed circumstance is smaller than the maximum cyclic shift supported by the ZC sequences in Sub-group i+1 under the high speed circumstance, the maximum cyclic shift supported by the ZC sequences in Sub-group i under the high speed circumstance is larger than the maximum cyclic shift supported by the ZC sequences in Sub-group i+1 under the high speed circumstance, wherein, the second group dividing unit applies different principles to the sub-groups in adjacent groups.

Wherein, the sequencing process of the second group dividing unit may be performed in the increasing order or in the decreasing order, and the adjacent groups should be sequenced in different orders.

Wherein, the sequencing process of the second group dividing unit needs to be performed according to a certain granularity. The granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)} and P_(i) ^(g)<P_(i+1) ^(g), thus, (1) the sequencing performed in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g); (2) the sequencing performed in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(s−i+2) ^(g), and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g).

Wherein, the maximum cyclic shift of the ZC sequences is N_(CS)=min(du,N_(ZC)−2·du) wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of the ZC sequence. The distance between the correlation peak and the correlation peak alias thereof is

${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of the ZC sequence, and m is the minimum positive integer which makes

$\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer. Wherein, the sequence dividing unit can divide a plurality of ZC sequences, being sequenced after the first sequencing, into two groups according to the cubic metrics of Quadrature Phase Shift Keying.

The descriptions above are only preferable embodiments of the present invention, which are not used to restrict the present invention. For those skilled in to the art, the present invention may have various changes and variations. Any amendments, equivalent substitutions, improvements etc. within the spirit and principle of the present invention are all included in the scope of the claims of the present invention. 

What is claimed is:
 1. A method for sequencing Zadoff-Chu (ZC) sequences of random access channel, comprising the following steps: Step 202, dividing, by a first group dividing unit, Nq ZC sequences into a plurality of groups according to a cubic metrics of the ZC sequences, wherein 1<=Nq<=Nzc−1, Nzc is the length of the ZC sequence; Step 204, sequencing, by a second group dividing unit, the ZC sequences, according to a maximum cyclic shift supported by the ZC sequences under a high speed circumstance, within each group to form a plurality of sub-groups; and Step 206, sequencing, by a sequencing unit, the ZC sequences within each of said plurality of sub-groups according to the cubic metrics of the ZC sequences, wherein, adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of two adjacent groups are sequenced in the same order; wherein, said maximum cyclic shift N_(CS)=min(du,N_(ZC)−2·du), wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of said ZC sequence.
 2. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, said Nq ZC sequences are divided into G groups, wherein, 1≦G≦Nq, the relation between the serial number of each of said plurality of groups and the cubic metrics of the ZC sequences in each of said plurality of groups is: the cubic metrics of the ZC sequences in Group i are smaller than the cubic metrics of the ZC sequences in Group i+1, or the cubic metrics of the ZC sequences in Group i are larger than the cubic metrics of the ZC sequences in Group i+1.
 3. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, said Nq ZC sequences are divided into two groups according to the cubic metrics of Quadrature Phase Shift Keying.
 4. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, in Step 202, firstly, said Nq ZC sequences are sequenced, in decreasing order or in increasing order, according to the cubic metrics of the ZC sequences, and then, a sequencing result is divided into a plurality of groups according to one or more cyclic shift thresholds.
 5. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, in Step 204, the sequencing is performed in increasing order or in decreasing order, and the adjacent groups are sequenced in different orders.
 6. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, in Step 204, the sequencing is performed according to a preset granularity.
 7. The method for sequencing the ZC sequences of the random access channel according to claim 5, wherein, a granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)}, and P_(i) ^(g)<P_(i+1) ^(g), and the sequencing performed in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high speed circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), and the sequencing performed in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high speed circumstance is smaller than P_(s−i+2) ^(g), and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each ZC sequence in Sub-group i under the high-speed circumstance is smaller than P₁ ^(g).
 8. The method for sequencing the ZC sequences of the random access channel according to claim 1, wherein, said distance between the correlation peak and the correlation peak alias thereof is ${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of said ZC sequence, and m is the minimum positive integer which makes $\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.
 9. The method for sequencing the ZC sequences of the random access channel according to claim 2, wherein, said maximum cyclic shift N_(CS)=min(du, N_(ZC)−2·du) wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of said ZC sequence.
 10. The method for sequencing the ZC sequences of the random access channel according to claim 3, wherein, said maximum cyclic shift N_(CS)=min(du, N_(ZC)−2·du) wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of said ZC sequence.
 11. A device for sequencing Zadoff-Chu (ZC) sequences of random access channel comprising: a first group dividing unit, configured to divide Nq ZC sequences into a plurality of groups according to a cubic metrics of the ZC sequences of the random access channel, wherein 1<=Nq<=Nzc−1, Nzc is the length of the ZC sequence; a second group dividing unit, configured to sequence the ZC sequences within each group to form a plurality of sub-groups, according to the maximum cyclic shift supported by the ZC sequences under a high speed circumstance; and a sequencing unit, configured to sequence the ZC sequences in each of said plurality of sub-groups according to the cubic metrics of the ZC sequences, wherein, adjacent sub-groups in the same group are sequenced in different orders, while the sub-groups at the boundary of two adjacent groups are sequenced in the same order; wherein, said maximum cyclic shift N_(CS)=min(du,N_(ZC)−2·du), wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of said ZC sequence.
 12. The device for sequencing the ZC sequences of the random access channel according to claim 11, wherein, said first group dividing unit divides said Nq ZC sequences into G groups, wherein, 1≦G≦Nq, the relation between the serial number of each of said plurality of groups and the cubic metrics of the ZC sequences in each of said plurality of groups is: the cubic metrics of the ZC sequences in Group i are smaller than the cubic metrics of the ZC sequences in Group i+1, or the cubic metrics of the ZC sequences in Group i are larger than the cubic metrics of the ZC sequences in Group i+1.
 13. The device for sequencing the ZC sequences of the random access channel according to claim 11, wherein, said first group dividing unit divides said Nq ZC sequences into two groups using the cubic metrics of Quadrature Phase Shift Keying as a threshold.
 14. The device for sequencing the ZC sequences of the random access channel according to claim 11, wherein, said second group dividing unit performs the sequencing of the ZC sequences in each group in increasing order or in decreasing order, and the adjacent groups are sequenced in different orders.
 15. The device for sequencing the ZC sequences of the random access channel according to claim 11, wherein, said second group dividing unit performs the sequencing according to a preset granularity.
 16. The device for sequencing the ZC sequences of the random access channel according to claim 14, wherein, a granularity of the cyclic shift of Group g is P^(g)={P₁ ^(g), P₂ ^(g), . . . , P_(s) ^(g)}, and P_(i) ^(g)<P_(i+1) ^(g), performing the sequencing in the increasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(i+1) ^(g), and larger than or equal to P_(i) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed g circumstance is smaller than P₁ ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), performing the sequencing in the decreasing order means: when 1<i<s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than P_(s−i+2) ^(g), and larger than or equal to P_(s−i+1) ^(g), when i=1, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is larger than or equal to P_(s) ^(g), when i=s, the maximum cyclic shift supported by each sequence in Sub-group i under the high speed circumstance is smaller than p₁ ^(g).
 17. The device for sequencing the ZC sequences of the random access channel according to claim 11, wherein, said distance between the correlation peak and the correlation peak alias thereof is ${du} = \left\{ {\begin{matrix} {\frac{{m \cdot N_{ZC}} - 1}{u},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} \leq {{floor}\left( {N/2} \right)}} \\ {{N_{ZC} - \frac{{m \cdot N_{ZC}} - 1}{u}},} & {{{when}\mspace{14mu}\frac{{m \cdot N_{ZC}} - 1}{u}} > {{floor}\left( {N/2} \right)}} \end{matrix},} \right.$ wherein, u is the serial number of said ZC sequence, and m is the minimum positive integer which makes $\frac{{m \cdot N_{ZC}} - 1}{u}$ a positive integer.
 18. The device for sequencing the ZC sequences of the random access channel according to claim 12, wherein, said maximum cyclic shift N_(CS)=min(du, N_(ZC)−2·du) wherein, du is the distance between a correlation peak and a correlation peak alias thereof, and N_(ZC) is the length of said ZC sequence. 